The present invention relates to sails and more particularly, to a process and apparatus for casting sails and the reinforced sails produced thereby.
Sails are three dimensional (solid rather than plane) surfaces. They are so to provide lift for the sailplan and therefore for the sailboat. Presently, substantially all sails are because of their size, traditionally, made of panels or sections which are arranged in one way or another, usually at the discretion of a sail designer.
When placed on a planar surface such as a floor and when in use and set upon the sailplan, most sails exhibit a distinct element of vertical camber throughout. The body of the sail performs three missions. First, it separates its high pressure side from its low pressure side. Second, it supports the sail s internal structure and retains its structural elements and members in the exact positions, which they are intended to occupy. Third, it provides the sail with the durability and resilience which is illustrated in a tendency to resist damage from tearing, from creasing and folding, from vibrating (luffing) in the wind, and from chafing against the sailplan s components such as mast, standing rigging and lifelines.
The current state of the sail manufacturing art results in a sail product whose body is a sandwich-type construction. Specifically, such sails are comprised of a skeletal structure of load-bearing fibers or yarns that is covered on each side by layers of polyester film, woven taffeta materials, or both. The outside layers are fastened to the internal skeletal yarn structure and to each other by the use of adhesives and/or by the application of heat and pressure in the manufacturing process. Sails employing the concepts of these patents are now employed widely and particularly by racing yachts.
Certain prior art sail manufacture includes a method of fabrication employing panels which are assembled and to which structural yarns are subsequently applied.
An alternate sail manufacture system includes a method for casting a sail from liquid synthetic resin using a mold comprised of numerous sections which can be altered in position to establish the desired sail contour. Obviously, the size of the sail that can be produced is limited by the size of the mold, and the costs of fabricating such a mold. Moreover, there is no reinforcement provided in such a cast structure. In another prior art system, a process for making a sail includes the use of panels assembled into a substrate and draped over a table configurable to the contours desired for the sail. Reinforcing yarns or fibers are laid onto the substrate in a pattern. This process involves costly and time consuming initial steps of precutting and then carefully assembling the panels to provide the substrate which will then assume the contours of the table.
What is needed in the art is a system that produces a casting of a seamless sail formed in one piece. The system should include the addition of reinforcing yarns in a pattern within a matrix of resin. The need exists for a low cost sail having desirable form and durability that can be rapidly produced.